Process of reclaiming rubber from vulcanized-rubber waste.



Patented Dot. I7, |899.

1 A. H.' MARKS. R PROCESS 0F RECLAIMING RUBBER FROM VULCANIZED RUBBERWASTE.

(Appueazicn mea F013. 2 7, 1899.)

(Specimens.)

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ARTHUR H. MARKS, OF AKRON, OHIO.

PROCESS OF RECLAlMlNG RUBBER FROM VULCANIZED-RUBBER WASTE.

SPECIFICATION forming part of Letters Patent No.' 635,141, dated October17, 1899.

Application filed February 2'7, 1899. Serial No. 706,982. (Specimens.)

To all whom t ptn/,y concern:

Be it known that I, ARTHUR H. MARKS, a citizen ofthe UnitedStates,residing at Akron, in the county of Summit and State of Ohio,have invented a certain new and useful Improvement in Processes ofReclaiming Rubber from Vulcanized-Rubber Waste, of which thefollowingisa full, clear, and exact description, reference being had tothe accompanying drawing. i

The invention has for its object the devulcanization of the rubber invulcanized-rubber waste and the reclaiming of such rubber in a conditioncapable of being used for the various purposes for which fresh rubber isused and of being revulcanized.

The invention consists in subjecting the ground rubber waste, whensubmerged in a dilute alkaline solution-as, for example, athree-per-cent. solution of caustic soda--to the action of great heatsayfrom 344o to 370o Fahrenheit, more or less-for twenty hours,

.more or less, under conditions which prevent the evaporation of anyconsiderable quantity of the solution.

In the best method now known to me for carrying out the process theiinely-ground` rubber waste is put into a suitable vessel,togetherwithadilute alkaline solution, a threeper-cent. solution ofcaustic soda being preferred, there being enough of. the solution topermeate the rubber and completely submergeit. This Vessel is thensealed up to prevent any considerable evaporation of the solution duringthe progress of the process, and the contents of the vessel are thenheated to 344O to 370 Fahrenheit, more or less, and this temperature ismaintained for twenty hours, The smaller the percentage of sulfur whichthe rubber contains the less the heat required and the shorter time itis necessary to maintain the heat; but as a practical process to be usedday in and day out with vulcanized-rubber waste of various sorts as itis for sale in the open market a temperature of 3440 to 370.o Fahrenheitmaintained for twenty hours has been found to produce the resultsought-viz., the devulcanization of the rubber and incidentally theelimination of the fabric which the waste contained. The product of theprocessis then thoroughly Washed to remove the chemicals, and thereremains devulcanized rubber having substantially the characteristics offresh rubber and capable of being used in like manner and for likepurposes.

The'drawing is a sectional View of an apparatus capable of use incarrying out the process. v

A represents the vessel into which the ground waste and the chemicalsolution are placed, ctr being the cover thereof, by which the vesselmay be sealed.

B represents an outer receptacle capable of containing the vessel A andof being tightly closed. lSteam is let into the outer 1vessel through apipe O at a pressure of one hundred and twenty-live pounds, more orless, (equivalent to a temperature of 344 Fahrenheit,) and is kept atthis pressure for the entire time necessarysay twentyhours. If thesteam-pressure is increased, the time necessary for the production ofthe result sought will be reduced. A

I have had heretofore no facilities for conducting the .process at agreater temperature than is produced by one hundred and seventy-Iivepounds steam-pressure-namely, 3700 Fahrenheitwat which temperature,however, equally good results are obtained in a somewhat shorter time.The results of such experiment-s as I have been able to make withtemperature above that of steam of one hundred and seventy-five poundspressure seem to indicate that the saving of time which results is notworth the additional cost and that the most economical method ofpracticing the process consists, as before stated, in Y heatingthemixture in a tightly-closed vessel by means of steam at a pressure ofone hundred and twenty-tive pounds for about twenty hours.

Having described my invention, I clai1n- The described process fordevulcanizing rubber waste which consists in submerging the nely-groundrubber waste in a dilute alkaline solution in a sealed vessel, inheating the contents of the vessel to a temperature of 344 Fahrenheitmore orless substantially as specified, and in maintaining saidtemperature for twenty hours more or less substantially as specified.

In testimony whereof I 'hereunto affix my signature in the presence oftwo witnesses.

ARTHUR H. MARKS. W'itnesses:

E. L. THURs'roN, PHILIr EKNowLroN.

IOO

